1. Field of the Invention
The invention relates generally to a single-sideband modulation method and apparatus and more particularly to a single-sideband modulation method and apparatus using only one transmitting tube.
2. Discussion of the Background
Prior art relating to this invention is described in the German book: H. Meinke and F. W. Gundlach, Taschenbuch der Hochfrequenztechnik (Pocketbook of Radio-Frequency Engineering), Springer-Verlag Berlin/Heidelberg/New York 1968, pages 1323-1325. In this publication, a single-sideband modulator for a large frequency range of the carrier oscillation and a wide low-frequency band according to Lenehan is described, in which modulator phase dividers generating component signals phase-shifted by 90.degree. are provided for both frequency ranges. These component signals feed two ring modulators which, in turn, drive three final amplifier tubes. A disadvantage of this arrangement is that three tubes are needed which must be operated within their linear range, that is to say in class A or class B mode.